Underground systems such as underground transportation systems conventionally employ many electrical and mechanical subsystems to maintain operation. For example, underground transportation systems (e.g., subways, trains) typically incorporate ventilation subsystems, power subsystems, control subsystems, and the like. Many of these subsystems typically fail or at least operate poorly or inefficiently when in contact with water, whether from environmental or man-made causes.
Ventilation subsystems, for example, typically operate to remove gases and particles from the air and to maintain operating temperatures of the underground transportation system. In this manner, the quality of breathable air underground and the operating temperatures are maintained at acceptable levels for the passengers and the technical requirements of the subsystems, respectively. If air quality is not maintained at an acceptable level, then passengers and operators of the underground transportation system may be negatively affected. Similarly, if the operating temperatures are not maintained at an acceptable level, then subsystems may fail, malfunction, and/or operate inefficiently. Therefore, ventilation of underground air is critical to maintain optimal conditions for underground transportation systems.
Rain, for example, may temporarily cause flooding in underground transportation systems. Similarly, water from fire hydrants on the surface may also flood underground transportation systems. Such water may cause pooling of water on, near, or over certain components of subsystems, causing failures, malfunctions, and/or inefficiencies of such subsystems.
Water typically enters underground transportation systems via ventilation grates on sidewalks and roads. MTA New York City Transit, for example, has between 30,000 to 40,000 ventilation grates. Conventionally, water entering ventilation grates has been removed via pumps. Such pumping can be inadequate in times of surface flooding due to heavy rain.
Therefore, it may be desirable to reduce and/or restrict water from entering underground transportation systems via vents. It may also be desirable to control the flow of water from the surface to underground transportation systems to maintain operating conditions and to reduce the need for water pumps.